The present invention relates to a condenser microphone and a method for manufacturing condenser microphones for a portable telephone, video camera and others.
FIG. 5 shows a sectional view of a conventional condenser microphone. The condenser microphone comprises a substrate 2, a field-effect transistor (FET) 3 mounted on the substrate 2, a back plate 5 mounted on the substrate 2 interposing a spacer 4, and a frame 8 mounted on the back plate 5 interposing a spacer 6. A diaphragm 7 as a movable electrode is secured to the underside of the frame, and a stationary electrode (not shown) is secured to the surface of the back plate 5.
When assembling the microphone, bottom portion 1a of a case 1 is not bent. The case 1 having a sound collecting hole 1b is inverted and the above described elements are mounted in the case 1. Then, the bottom portion 1a is bent as shown in FIG. 5.
In the conventional condenser, composition elements must be packaged in the case at every microphone and the bottom portion 1a must be bent.
Therefore, the productivity of the condenser microphone is low, the manufacturing cost high.